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AVR Programming in 64-bit Windows 7

A majority of the microcontroller programming I do these days involves writing C for the ATMEL AVR series of microcontrollers. I respect PIC, but I find the open/free atmosphere around AVR to be a little more supportive to individual, non-commercial cross-platform programmers like myself. With that being said, I've had a few bumps along the way getting unofficial AVR programmers to work in Windows 7. Previously, I had great success with a $11 (shipped) clone AVRISP-mkII programmer from It was the heart of a little AVR development board I made and grew to love (which had a drop-in chip slot and also a little breadboard all in one) seen in a few random blog posts over the years. Recently it began giving me trouble because, despite downloading and installing various drivers and packages, I couldn't get it to work with Windows Vista or windows 7. I needed to find another option. I decided against the official programmer/software because the programmer is expensive (for a college student) and the software (AVR studio 6) is terribly bloated for LED-blink type applications. "AStudio61.exe" is 582.17 Mb. Are you kidding me? Half a gig to program a microchip with 2kb of memory? Rediculous. I don't use arduino because I'm comfortable working in C and happy reading datasheets. Furthermore, I like programming chips hot off the press, without requiring a special boot loader.

I got everything running on Windows 7 x64 with the following:

Here's the "hello world" of microchip programs (it simply blinks an LED). I'll assume the audience of this page knows the basics of microcontroller programming, so I won't go into the details. Just note that I'm using an ATMega48 and the LED is on pin 9 (PB6). This file is named "blink.c".

#define F_CPU 1000000UL
#include <avr/io.h>
#include <util/delay.h>

int main (void)
    DDRB = 255;
        PORTB ^= 255;

Here's how I compiled the code:

avr-gcc -mmcu=atmega48 -Wall -Os -o blink.elf blink.c
avr-objcopy -j .text -j .data -O ihex blink.elf blink.hex

In reality, it is useful to put these commands in a text file and call them "compile.bat" Here's how I program the AVR. I used AVRDudess! I've been using raw AVRDude for years. It's a little rough around the edges, but this GUI interface is pretty convenient. I don't even feel the need to include the command to program it from the command line! If I encourage nothing else by this post, I encourage (a) people to use and support AVRDudess, and (b) AVRDudess to continue developing itself as a product nearly all hobby AVR programmers will use. Thank you 21-year-old Zak Kemble.

And finally, the result. A blinking LED. Up and running programming AVR microcontrollers in 64-bit Windows 7 with an unofficial programmer, and never needing to install bloated AVR Studio software.

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